Abstract
Light pollution is a form of rapidly-growing and global-scale environmental degradation in which excessive outdoor lighting affects the natural environment and the ecosystem. Poorly designed outdoor lighting not only wastes energy and money, but also robs us of our beautiful night sky. Effects of light pollution on the night sky can be evaluated by the skyglow caused by artificial lighting sources, through measurements of the night sky brightness (NSB). The Hong Kong Night Sky Brightness Monitoring Network (NSN) was established to monitor in detail the light pollution conditions in Hong Kong. Monitoring stations were set up throughout the city covering a wide range of urban and rural settings to continuously measure the variations of the NSB. Over 4.6 million zenith NSB measurements were collected from 18 distinct locations between May 2010 and March 2013. In this seminar, I will introduce the methodology of NSB monitoring. Key findings characterizing the overall light pollution condition in Hong Kong, temporal and geographical variations of NSB, and correlation between NSB and various natural and artificial factors will also be discussed. Results of the research established the effects of artificial lighting on the night sky, and provided scientific justifications for the ways to go for light pollution reduction and dark sky protection.